Technical feasibility of integrating concentrating solar thermal energy in the Bayer alumina process

Abstract

The paper presents the establishment of a pathway to progressively integrate solar thermal (CST) energy technologies into the current energy-intensive Bayer Process that produces calcined alumina from bauxite. This four-and-a-half-year program has developed three classes of CST technologies, low temperature steam production, solar syngas production and direct use of solar energy in the calciner, to enable a 29% to 45% solar share. In doing so, we ensure that continuous operation can be maintained, and that only minimal changes would need to be made to the refinery process, hence minimising the risk that industry takes on when introducing a new technology like this. In the present study, we have developed three process models for the low-temperature and high temperature processes using packages, such as the System Advisor Model (SAM), UNISIM, and Microsoft Excel, of the Bayer process to assess the impact of storage hour and solar resource variability on solar share or annual fuel saving and CO2 reduction for CST technologies relative to the conventional Bayer process.